Nitrogen Fixing Leguminous Symbioses

Nodules produced on legume roots by root-nodule bacteria provide the major nitrogenous input into natural and agricultural systems worldwide. This book provides an in-depth and up-to-the-minute analysis of what is known about this symbiosis, its origins, the process of nodule formation and development, and the biochemistry and genetics of nodular nitrogen fixation. It also reviews the physiology of the root-nodule bacteria themselves, their ecology in both natural and agricultural systems, and how we can introduce new legumes along with the bacteria they require. This book is recommended for scientists working with root nodule bacteria or host legumes, agronomists, forestry scientists, and soil scientists.

During the past three decades there has been a large amount of research on biological nitrogen fixation, in part stimulated by increasing world prices of nitrogen-containing fertilizers and environmental concerns. In the last several years, research on plant--microbe interactions, and symbiotic and asymbiotic nitrogen fixation has become truly interdisciplinary in nature, stimulated to some degree by the use of modern genetic techniques. These methodologies have allowed us to make detailed analyses of plant and bacterial genes involved in symbiotic processes and to follow the growth and persistence of the root-nodule bacteria and free-living nitrogen-fixing bacteria in soils. Through the efforts of a large number of researchers we now have a better understanding of the ecology of rhizobia, environmental parameters affecting the infection and nodulation process, the nature of specificity, the biochemistry of host plants and microsymbionts, and chemical signalling between symbiotic partners. This volume gives a summary of current research efforts and knowledge in the field of biological nitrogen fixation. Since the research field is diverse in nature, this book presents a collection of papers in the major research area of physiology and metabolism, genetics, evolution, taxonomy, ecology, and international programs.

The Nitrogen-Fixing Legume-Rhizobium Symbiosis, Volume 94, the latest release in the Advances in Botanical Research series, highlights new advances in the field, with this new volume presenting interesting chapters on The diversity of legume-rhizobium symbioses, Parasponia; an evolutionary outlier of rhizobium symbiosis, Rhizobium diversity in the light of evolution, Genomes of rhizobia, Gene regulation by extracytoplasmic function (ECF) sigma factors in alpha-rhizobia, Early symbiotic signaling between Plant and Bacteria, Rhizobia infection, a journey to the inside of plant cells, Differentiation of symbiotic nodule cells and their rhizobium endosymbionts, Nodule Organogenesis, Nitrogen Fixation by the Legume-Rhizobium Symbiosis, and much more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Advances in Botanical Research series Updated release includes the latest information on the Nitrogen-Fixing Legume-Rhizobium Symbiosis

For researchers and graduates with any interest in plant or soil sciences, this fascinating study will be a godsend – it’s the complete state of the art with regard to actinorhizal symbioses. The self-contained sixth volume of a comprehensive series on nitrogen fixation, it includes chapters that deal with all aspects of this symbiosis between actinorhizal plants and nitrogen-fixing bacteria. It also contains information both about symbionts and their ecological role and use. Other chapters tackle the global distribution of different actinorhizal plants and their microsymbionts and how this impacts the question of co-evolution of the micro- and macrosymbionts as well as comparing the actinorhizal and leguminous symbioses. No other book provides the up-to-date and in-depth coverage of this volume.

Genetical aspects and taxonomy; Quality of legume inoculants; Field experiments on nitrogen fixation by nodulated legumes; Legume nitrogen fixation and the environment; Nitrogen fixing symbioses in non-leguminous plants.

General information on the symbiotic nitrogen fixation. Isolation, identification and counting of rhizobia. Production of an inoculant and inoculation of legumes. Experiments.

This important book provides a comprehensive review of our current knowledge of the world's leguminous plants and their symbiotic bacteria. Written by Professor Janet Sprent, a world authority in the area, Legume Nodulation contains comprehensive details of the following: An up to date review of legume taxonomy and a full list of the world's genera Details of how legumes are distributed throughout the world A review of the evolution of legume nodulation Comprehensive details of all microorganisms known to be symbiotic with legumes Ecological and environmental aspects of legume-bacteria symbiosis Legume Nodulation is an essential purchase for plant scientists, agronomists, ecologists and microbiologists. Libraries in all universities and research establishments where biological and agricultural sciences are studied and taught should have copies of this landmark publication.

The reciprocal exchange of chemical signals between legume and rhizobium leads to the establishment of Root Nodule Symbiosis (RNS). The discoveries of the Nodulation Factor (NF) and nod genes, along with the discoveries of the relevant genetic plant factors, have expanded our understanding of how legume-rhizobial interactions constitute a successful mutualistic symbiosis. Symbiotic nodule formation can be divided into the following molecular events: (i) the reciprocal exchange of signals; (ii) epidermal recognition of symbiotic partner and infection thread formation; (iii) nodule organogenesis; (iv) the establishment of a microaerophilic environment to provide nitrogenase the ideal condition to work; and, (v) modulation of immunity to host rhizobium inside the nodule cells. The number of nodules in a plant is maintained via a process of systemic signaling, known as ‘autoregulation of nodulation’ (AON), that acts as a negative signal to control nodule number in low nitrogen conditions and inhibit nodule initiation in an optimally nitrogen-fed plant. Over 200 plant genes have been discovered up to now and these discoveries have given us a broad understanding of RNS.

In the 100 years since the legume-Rhizobium symbiotic nitrogen fixation interaction was first described, interest in this field has grown rapidly. The types of studies have been cyclical in nature, involving a cross-section of disciplines. The availability of cheap nitrogenous fertilizers caused much of the biological nitrogen fixation research to become more theoretical in the developed world. The high cost of energy, coupled with environmental concerns and the interest in sustainable agriculture, has stimulated research in symbiotic nitrogen fixation. The development of modern genetic techniques has resulted in interdisciplinary research on plant-microbe interactions controlling nitrogen fixation. This has resulted in a better understanding of environmental factors influencing the nodulation process, chemical signalling between the symbiotic partners and the nature of the specificity between host plant and microsymbiotant. This volume summarizes the diverse research efforts in biological nitrogen fixation by presenting a collection of papers in the areas of physiology and metabolism, taxonomy and evolution, genetics and ecology.